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A facile, time-saving and one-step process to prepare graphene-based materials with excellent comprehensive capacitive performance is very promising for practical applications. Here, porous nitrogen-doped graphene/carbon nanotubes composite (PNGC) with loosened structure was prepared by pyrolysis method and the porous structure of PNGC was controlled by combined action of urea and low-cost lignosulfonate. PNGC is equipped with porous structure and thin graphene nanosheets, and meanwhile possess numerous active sites and high surface areas. Importantly, PNGC exhibits a high specific capacitance of 246.6 F g −1 at a current density of 0.5 A g −1 and high stability of 96.5% capacitance retention ratio after 2000 cycles at 100 mV s −1 , indicating an excellent performance of PNGC. Furthermore, the corresponding mechanism of pore formation in PNGC is hence proposed. This work of obtaining PNGC is of paramount importance for the future practical application of electrode materials for supercapacitor application. [ABSTRACT FROM AUTHOR]

The gram-scale synthesis of graphene based mesoporous SnO 2 composite (G-M-SnO 2 ) has been successfully realized based on kirkendall effect. When used as anode for lithium ion batteries, it delivers a high reversible capacity of 1354 mAhg −1 after 50 cycles at 100 mAg −1 and excellent rate capability of 664 mAhg −1 at 2 Ag −1 . The outstanding lithium storage performance mainly results from the synergistic effect of the ultrasmall SnO 2 and conductive graphene nanoparticles, which not only enhanced the conductivity of the whole electrode but also provide buffer matrix for the expansion of SnO 2 nanoparticles during charge-discharge process. Furthermore, the ultra-small size of SnO 2 shortens the diffusion length of Li + /e − in SnO 2 . [ABSTRACT FROM AUTHOR]